1. Controller
The party responsible for data processing on this platform is Heimster, a product of PhaseShift AG, Zug, Switzerland.
This statement applies to the Heimster platform at heimster.ch as well as to related services, communication channels and application processes.
When commercial customers (such as brokers or property managers) use the agency and CRM functions to manage their own contact, prospect or applicant data, Heimster acts in this respect as a data processor on behalf of the respective company, which remains responsible under data protection law; the processing is carried out on the basis of a data processing agreement.
2. What data we process
2.1 Account data
When you register, we process in particular your name, email address and authentication data. If you use a magic link or passkey, we process the technical data required for this.
2.2 Profile, application and document data
Depending on how you use the platform, we process profile data, information about your housing situation, application documents, references, messages, viewing appointments and shared documents. Certain content may contain particularly sensitive personal data, such as copies of ID documents, proof of income or information about your family situation.
2.3 Listing and property data
Providers enter address, property and media data for their real estate. This includes descriptions, features, prices, images and process-related information about the rental or sales process.
2.4 Technical usage data
For the security, stability and operation of the platform, we process technical access data such as IP address, time, requested URL, browser type, referrer and system events. Server logs serve in particular for error analysis, abuse detection and system security.
2.5 Personalisation data
If you select a personalised level, we store search history, viewed listings and preferences derived from them locally on your device and use them to improve your experience. When you are logged in, signals derived from this may be merged with your profile.
2.6 Access and interaction data on shared content
When a provider makes documents available through a data room or a personal sharing link, we log the access: the time, the documents and pages opened, and the person the link was issued to. Protected views additionally carry a personalised watermark. The provider who granted access sees this record; it serves as proof of the release and protects confidential material.
2.7 Legal bases
We process personal data in accordance with Swiss data protection law and, where applicable, with the GDPR. Depending on the case, processing is carried out to fulfil a contract, on the basis of legitimate interests, due to legal obligations or based on your consent.
Our legitimate interests include in particular the secure provision of the platform, the prevention of fraud and abuse, quality assurance, the enforcement of claims, the stability and further development of the product and the analysis of usage to improve our services.
3. Data storage: where your data is held
Heimster runs on its own infrastructure in Switzerland. The application, the database, file and media storage, PDF generation and our audience measurement are operated at a Swiss infrastructure provider in Geneva. Personal data at rest - database content, uploaded documents and images, email content from connected mailboxes and backups - stays in Switzerland. Data is transmitted in encrypted form only (TLS).
For some functions, processing exclusively in Switzerland is not technically possible. In the following cases - and only in these - data is transferred abroad:
- AI functions: content an AI function requires is transferred to service providers outside Switzerland, today mainly in the USA. See the section on AI-supported functions for details.
- Email dispatch: we use specialised dispatch providers for reliable delivery. Every email also leaves our sphere of control once it is delivered to the recipient's provider.
- Connected mailboxes and calendars: this data is held by the provider you choose, Microsoft 365 or Google Workspace. We keep the access tokens encrypted in a key vault.
- Address, map and location services: for address search, geocoding and map display, individual address or coordinate queries are sent to external map services. Geodata, building data and public-transport data from public authorities are obtained from Swiss sources (swisstopo, cantonal geoportals, public timetable data).
- Security, domains, payment: services for bot protection, DNS and certificates, for payment processing and for sending the SMS code used in phone verification.
We do not sell personal data and we do not transfer it abroad for advertising purposes. For transfers to countries without an adequate level of data protection we rely on standard contractual clauses and supplementary technical safeguards.
4. Matching and demand aggregation
A core purpose of Heimster is matching: we compare your search criteria (search alerts and search profile) against properties from all providers on the platform – including properties not yet publicly listed. For this we process the search criteria you enter and, if you have created an application dossier, its contents. Heimster is the controller for this processing.
- Notifications: you receive emails when a matching property goes live or is made available to you early (preview). Every email contains an unsubscribe link.
- Aggregated demand numbers: providers only ever see anonymous, aggregated figures (e.g. “14 matching search alerts”) – never your name, contact details or other identifying information.
- No disclosure of your identity: a provider only learns who you are when you act yourself – for example by applying or making contact.
- Dossier data: information from your application dossier (e.g. income, household size) is used only for your own matching and for the anonymous “complete dossier” metric.
The legal basis is your consent at registration or when saving a search; matching is also the core of the service you sign up for.
You can end matching at any time: search alerts can be deleted or unsubscribed, search-profile data can be removed in your account, or the account deleted. Already generated aggregate numbers contain no personal data and remain unaffected.
Property atlas, owner enquiries and «My property»
When you send an enquiry about your property via the property atlas, we use your details (name, e-mail, phone, message, request, the market range shown) to contact you and pass them on to a suitable estate agency in your region – never to several at once. For «My property», after your confirmation (double opt-in), we store your e-mail address, the property details, any desired price and the monthly history. These details are only visible via your personal link and are not passed on. You can unsubscribe from the update at any time and delete all details on your page; they are also deleted when you delete your account.
Heimster in AI assistants (ChatGPT, Claude)
Through the public interface heimster.ch/mcp/public, AI assistants can query public listings, new-build projects, construction projects, market figures and location data for Swiss addresses – without an account. Contact details, names of private landlords and hidden addresses are never returned; for addresses hidden via heimster.ch/immobilien/ausblenden we only give figures for the municipality. For searches we only process technical data (the provider's IP address to prevent abuse) and count calls without search content. If you ask the assistant to send an enquiry, book a viewing, set up a search alert or follow the value of your property, it passes us the details needed for this (name, e-mail address, optionally phone number, message, number of people). We then send you a confirmation e-mail; only after your click does the enquiry go to the listing's provider, is the viewing booked or the search alert started – before that nobody receives your details. We delete unconfirmed requests one day after the link expires (valid for 48 hours) and all others after 30 days; the enquiry, booking or search alert itself remains, as with an entry on heimster.ch. What you enter in the assistant is governed by its provider. Links to Heimster carry a source tag (e.g. «chatgpt») so we can attribute visits. If you connect your Heimster account in the assistant (sign-in on heimster.ch, revocable at any time), it can send an application with your Heimster profile, register purchase interest and show your applications on your behalf – only when you ask for it in the chat; documents are never transferred through the chat.
Heimster Pro in AI assistants
Members of a Heimster Pro organisation can connect ChatGPT or Claude to their workspace via heimster.ch/mcp. The connection is only made after signing in with their own Heimster account and giving explicit consent; accounts without a Pro organisation get no access. The assistant then acts solely within that account's organisation and role – read-only access cannot change anything. At the user's request we pass the requested data of the organisation to the assistant, such as properties, listings, contacts, applications or viewings, including personal data of contacts, interested parties and applicants. The real-estate company remains responsible for this data; Heimster processes it as a processor under the data processing agreement, and processing within the assistant is governed by its provider (OpenAI or Anthropic). Actions with an effect outside the organisation – e-mails, publications, notifications – are only carried out after a preview and an explicit confirmation. The connection can be removed at any time under Settings → API; access ends immediately.
Heimster Hypo
Buyers can request mortgage advice through Heimster – from the financing step of the sales process or from their purchase interest. With their explicit consent we pass the data needed for this to our independent partner specialised in mortgages: name and contact details, the details on equity, income and obligations, the evidence uploaded for them, the property details and the purchase price, as well as the messages and documents exchanged as part of the request. The partner processes this data solely to check the financing, to advise and to obtain a financing approval.
The partner's access is limited to its own requests, protected by two-factor sign-in, and every access is logged. The agent only learns that a request is running and, in case of an approval, receives the approval letter as proof of financing – never the figures. Consent can be withdrawn at any time on the request page; the details, documents and messages stored at the partner are then deleted. We delete closed requests no later than twelve months after closing.
Interest analysis on property pages
On listings, showrooms, project pages and websites that real-estate marketers run on Heimster, we measure which content is viewed: pages visited, active time spent, sections and units viewed, downloads and clicks on contact and viewing functions. For this we use our own cookie («hm_vid», lifetime up to 400 days).
As long as you do not identify yourself, this data remains pseudonymous. If you enter your email address in a form, open a personal link or click a link in an email from the marketer, we link the browser to your email address – including earlier visits. The marketer running the page then sees your visits and an assessment of your interest (0–100) calculated from them, so they can advise you specifically. Other marketers do not see this data.
If you have a search profile with the marketer, they can refine it based on these visits: if you repeatedly look at properties outside your search profile (for example more rooms or another municipality), it is widened so that you receive more suitable offers. Every change is logged with its reason and can be undone.
- Visitors from Switzerland and Liechtenstein: the analysis is based on the legitimate interest in needs-based advice; you can object at any time.
- Visitors from other countries: the analysis only takes place with your consent (cookie settings).
- The marketer of the respective page is responsible for the analysis; Heimster processes the data on their behalf. Raw data is deleted after 13 months.
Objection: the «Object» link at the bottom of each affected page stops the measurement in your browser; data already recorded for this browser is deleted. You can also contact the marketer or us at any time.
Origin and use of Heimster accounts
On heimster.ch's own pages we use the same cookie («hm_vid») to record how you came to Heimster (referring website, campaign parameters, landing page) and which pages you view. If you register, we link this history to your account. We also record when you sign in.
This helps us understand how people find and use Heimster and improve the service. The analysis is done internally at Heimster only and is not passed on to third parties or agencies. The same rules as above apply (Switzerland and Liechtenstein: legitimate interest with a right to object; other countries: only with consent). Page views without an account are deleted after 180 days, an account's data when the account is deleted. This recording does not take place on agencies' websites and project pages.
5. AI-powered features
Heimster uses AI to create and summarise texts, to understand search and customer enquiries, to propose reply drafts, to prepare images, to evaluate documents and plans, and to check content for impermissible material before publication. For this we use the most capable models available. That makes it necessary in some cases for the content required - a text, an image, a document or the history of a conversation - to be transmitted to these providers, which are usually based in the USA. Depending on the task we use different providers. Only what the function needs is transmitted, and only for the duration of the processing. We will provide a list of the service providers we use on request.
You trigger most of these functions yourself. The automatic check of uploaded images and listing texts for impermissible content, by contrast, runs with every publication; it rests on our legitimate interest in a platform free of misuse.
No training on your data. We use these services through their business and API offerings. Under the terms that apply there, the content transmitted is not used to train these providers' models and is retained only briefly for abuse monitoring.
What we do not pass to AI services: uploaded application documents such as copies of identity papers, salary statements or debt-enforcement register extracts are not transmitted to AI services.
- AI-generated content consists of suggestions and must be reviewed before use.
Automated evaluations and ratings
Heimster automatically calculates metrics and ratings - for example how well a property matches a search profile, how complete a dossier is, or what takes priority in a provider's work list. Providers can have incoming items pre-sorted automatically on that basis. A rejection is never automatic; the decision is always taken by the provider.
6. Connected mailboxes and calendars (Microsoft 365 / Google Workspace)
Providers (brokers, property managers) can optionally connect their own email and calendar account with Microsoft 365 (Outlook) or Google Workspace (Gmail) to Heimster. The connection is made exclusively via the official OAuth process of the respective provider; Heimster never receives the password. The authorisation is granted by the provider itself and can be revoked at any time – in Heimster via “Disconnect mailbox” or directly in the security settings of the respective Microsoft or Google account.
After connecting, Heimster processes the following data from the connected account on behalf of the provider:
- Email (read): inbox and sent messages, in order to detect and classify incoming mail (e.g. genuine enquiry vs. automated message/newsletter) and assign it to the appropriate properties and contacts in the CRM.
- Email (send): sending replies and business messages from the provider's own address when this is triggered in Heimster.
- Calendar: reading the connected calendar for the appointment overview as well as creating, changing and deleting the appointments managed by Heimster (viewings, handovers, manually created appointments), including invitations to participants.
- Profile: the connected email address and the display name to identify the mailbox.
The OAuth tokens required for access are stored encrypted in a key vault; the actual token does not leave this vault. Access is strictly per user – Heimster does not merge third-party mailboxes, and the Heimster team has no access to the emails of the connected mailboxes.
The synchronised messages are stored in our database in Switzerland so that allocation, search and history work. If the mailbox is disconnected, we revoke access, delete the stored token and remove the synchronised messages from Heimster. If the provider uses the AI reply drafts, the content of the relevant thread is transmitted to our AI service provider for that single request (see the section on AI-supported functions).
Limited use (Google API Services User Data Policy / Limited Use): The use of information received via Google APIs (Gmail, Google Calendar) complies with the Google API Services User Data Policy, including the Limited Use requirements. In particular:
- We use this data exclusively to provide and improve the mailbox and calendar functions visible to the provider.
- We do not sell this data and do not share it for advertising purposes.
- We do not transfer or use this data for other purposes, except where necessary to provide the function, for security reasons, to comply with applicable laws or as part of a merger/acquisition with consent.
- No human reads this data, except (a) with the provider's explicit consent, (b) for security purposes (e.g. abuse investigation), (c) to comply with applicable laws or (d) when the data is aggregated and anonymised for internal operational purposes.
- No AI training: We do not use data from the connected mailbox or calendar to develop, train or improve generalised or non-personalised AI/ML models. AI features operate exclusively within the provider's own, provider-triggered processing.
The same principles apply mutatis mutandis to Microsoft 365 (Microsoft Graph): access only within the authorised scope, exclusively to provide the functions, no sale, no advertising use and no training of generalised AI models.
7. Disclosure and international data transfers
We only share your data insofar as this is necessary for the operation of the platform, legally permissible or initiated by you. This includes in particular:
- Our hosting partner in Switzerland for the platform's servers, database and storage
- Dispatch providers for transactional and business email
- AI service providers for the tasks described in the section on AI-supported functions
- Services for payment processing and for the SMS code used in phone verification
- Services for bot protection, DNS, certificates and the registration of customer domains
- Map services for address search, geocoding and map display
- Swiss public bodies for geodata, building data and public-transport data (swisstopo, cantonal geoportals, public timetable data)
- Microsoft 365 or Google Workspace, where a provider connects their own mailbox or calendar
- Property portals, where a provider publishes a listing there
- Social networks (Facebook, Instagram, LinkedIn), when a provider connects their account to Heimster: through the official sign-in process we receive the name, ID and an access token stored in encrypted form, in order to publish the posts triggered by the provider and to retrieve their reach. The connection can be removed at any time; we then delete the token and the account details.
- External service providers, a customer's own programs and AI assistants that they connect themselves through our interfaces
We will provide a list of the service providers we use on request.
Commercial customers can also connect Heimster to their own programs and to AI assistants through interfaces - an API key or an MCP connection. Whatever such an access queries is passed to the service concerned; the customer company establishes the connection itself, decides on its scope and remains responsible for it. Any access can be revoked at any time.
Some recipients are located outside Switzerland or the EEA, in particular in the USA. In these cases we rely on appropriate safeguards such as standard contractual clauses and supplementary technical protective measures.
Depending on the function, recipients act as data processors on our behalf or as independent controllers when they process the received data for their own legally permissible purposes. When data is passed on to a provider as part of an application or contact request, that provider processes the received information under its own data protection responsibility.
8. Retention
We store personal data only for as long as this is necessary for the respective purposes or legal obligations exist. Typical periods in the current product logic are:
- Account data until the account is deleted, then with a short security buffer
- Applications and the associated documents for as long as they are needed for the process and to make the decision traceable; providers can delete them at any time
- Messages and communication histories, as a rule until the account is deleted or until deletion as part of our product logic
- Listing and property data, as a rule until deactivation or deletion, subject to legal or documentation-related retention
- Server logs only for as long as needed for error analysis, abuse detection and system security
- Locally stored preferences until you revoke or reset your selection
- Email content from connected mailboxes until the mailbox is disconnected, deleted thereafter
- Access logs for data rooms and shared documents until the related property or transaction is deleted
- Invoicing and contract records for ten years under the statutory retention obligation
10. Fraud prevention, security and authorities
We also process personal data in order to detect, investigate and prevent abuse, fraudulent listings, phishing, unauthorised access, violations of our terms of use and other security incidents.
Where necessary, relevant information may be analysed internally, linked with technical security data and passed on to external specialist bodies, advisers, law enforcement authorities, courts or other competent bodies, where there is a legal basis for this or where this is necessary to protect our legitimate interests.
11. Service communication and marketing
We send you product- and contract-related communications insofar as this is necessary for using Heimster. This includes in particular account and security notices, application and viewing updates, message notifications, document requests and transactional emails.
If you activate saved searches, notifications or other optional communication features, we use your contact data to deliver this content to you. General marketing or advertising communication takes place only within the scope of applicable law and can, where provided for, be unsubscribed from at any time.
If a provider contacts you via Heimster – for example because your search or contact profile matches a listing – the respective provider is itself responsible for this communication under data protection and competition law; Heimster only provides the technical infrastructure for this.
12. Your rights
Under the applicable data protection law, you have in particular the rights to information, rectification, erasure, restriction, data portability, objection and withdrawal of your consent. If you are resident in the EEA, you can also contact the competent data protection authority.
We usually respond to requests within 30 days. In complex cases this period may be extended, of which we will inform you.
13. Contact
Please direct questions about data protection to privacy@heimster.ch.